The invention relates to a method for translating a graphical workflow in a textual description.
In the world of process automation and process monitoring standard automation systems for controlling the widest conceivable variety of machines and plants are state of the art. Such technology covers in particular a broad range of products which are offered by the Siemens Corp. under its SIMATIC® product family within the field of manufacturing execution systems (MES). An extensive line of products for solving the technical tasks in question such as counting, measuring, positioning, motion control, closed-loop control and cam control enhance the performance capabilities of appropriate process controllers. A variety of configurations enable the implementation of flexible machine concepts.
In this context a broad range of IT solutions exist to connect the actual hardware close to the technical and/or logistical process to the application layer of the client driving the installation. Manufacturing execution systems have therefore been developed to meet all of the requirements of a service oriented architecture (SOA) to integrate seamless into a totally integrated automation (TLA). A plug & play architecture, in which the individual functions can be easily combined and configured with each other thereby forms the basis for this success thereby simplifying the complex structures of controlling a manufacturing plant or the like.
These demands very often require in the backbone rather complicated and sophisticated software solutions which enable the approach of totally integrated automation. In view of this, the software engineers very often use production moduler to define the plant model and its standard operating procedures and create the respective new software by means of a high level graphical language which identifies the workflow of activities within the software. Subsequently, this string/term of high level graphical language is translated into a client based software language executable on the machine language level. This translation requires tremendous efforts in programming and need serious testing to check whether the translated program behaves the same as the original string/term of the high level graphical language.
For modeling the production system it is required to divide the productive process in many steps (hereinafter called product segments) so that each of the product segments represents a simple action that can be controlled by the MES system. This subdivision must take care of all dependencies existing between the product segments in order to guarantee that the entire production will be executed in the correct way. In this context, graphical programming has become more and more popular in the last years, due to its ease of use and clarity. As a result, many programming tools are based on this graphical approach. Graphical programming usually follows proprietary rules that very often do not require to build structured workflows. An example is a production modeler within a manufacturing execution system which assists to generate a virtual workflow of the production process.
In recent years, the standardization of process languages and their graphical programming is emerging. Such process languages are structured. For example BPEL (Business Processes Execution Language) is a structured language for the workflow code. Further information about the BPEL standard can be found on the web site http://www-106.ibm.com/developerworks/webservices/library/ws-bpel/. Another example is the ANSI/ISA/95 standard which has been released in order to standardize graphical language and its programming within manufacturing execution systems.